Referring to FIG. 2, a conventional linear slide comprises a slide rail (1) extending longitudinally and a slider (2) disposed on the slide rail (1), such that the slider (2) can be reciprocated on the slide rail (1). According to the requirements of the working environment, a working platform (3) is further installed on a mounting surface (211) of a platform (21) of the slider (2) so that the working platform (3) can be moved along with the slider (2) to perform the required operation.
In general, the mounting surface (211) of the platform (21) is ground when the slider (2) is manufactured. The roughness Ra can only be controlled at a minimum of about 0.2 microns by grinding.
The inventor found that when the working platform (3) is installed on the mounting surface (211) of the platform (21) of the slider (2) and the mounting surface (211) is reduced to a certain extent, the foot portions (22) of the slider (2) straddling the slide rail (1) is slightly deformed due to the force for locking the working platform (3) to the mounting surface (211). For example, as shown in FIG. 3 and FIG. 4, the foot portions (22) of the slider (2) slightly retract or expand randomly according to different installation conditions. In the figures, the initial interval between the two foot portions (22) is D. When the foot portions (22) are deformed because the mounting surface (211) is mounted with the working platform (3), the interval between the two foot portions (22) is d. In order to indicate the deformation of the foot portions (22) of the slider, the figures are shown with a more exaggerated deformation, which does not represent the deformation of the actual product. When the slider (2) and the mounting surface (211) are smaller, the effect of the roughness of the mounting surface (211) on the deformation of the foot portions (22) is greater after the working platform (3) is installed.
FIG. 5A and FIG. 5B illustrate another impact caused by the deformation of the foot portions (22) of the slider (2). FIG. 5A shows the undeformed configuration. When rolling members (4) are placed between the slider (2) and the inner surfaces of the foot portions (22) respectively, a clearance (t) is formed between the rolling member (4) and the inner surface of the foot portion (22). The clearance is designed to allow the rolling members (4) to roll smoothly without causing the phenomenon that the slider (2) vibrates/shakes or does not run smoothly. As shown in FIG. 5B, when the foot portions (22) of the slider (2) are deformed, for example, the two foot portions (22) are retracted or expanded, and therefore when the rolling members (4) are placed between the slider (2) and the slide rail (1), the clearance between the rolling member (4) and the inner surface of the foot portion (22) of the slider (2) becomes larger or smaller, so that the variation of the clearance is Δt=t′−t. If the variation Δt of the clearance is too big, the slider (2) will vibrate or shake. As a result, the operation error of the working platform (3) becomes larger, affecting the operation precision. If the clearance is too small, the slider is not running smoothly to affect the operation precision.
Referring to FIG. 6, the reason for this phenomenon is that the mounting surface (211) is rough, so that the working platform (3) is in multi-point contact with the mounting surface (211) of the platform (21) of the slider (2). The smaller the mounting surface (211) is, the unevenness of the roughness is more obviously. Therefore, when the mounting surface (211) is mounted with the working platform (3), the mounting surface (211) bears extremely large stress. Because the roughness is uneven, the force is applied unevenly, resulting in deformation of the foot portions (22).
For a larger slider having a larger mounting surface, such unevenness of the surface roughness can be neglected. Because of increased rigidity of the foot portions, the foot portion won't be deformed easily due to the roughness of the mounting surface. Therefore, the deformation can be ignored. For a miniature slider and its mounting surface, the deformation in the application will result in a certain impact on accuracy. For a miniature slide, such a slight deformation will affect the performance of working accuracy. Accordingly, the inventor of the present invention has devoted himself based on his many years of practical experiences to solve these problems.